Futures do not trade around the clock, and the platform does specific things at the daily close. Knowing them prevents the most common surprise on the platform: coming back to find a position gone.
When futures trade
The CME week opens on Sunday at 17:00 CT and runs until Friday at 16:00 CT. Inside that, there is a break every day from 16:00 to 17:00 CT.
Your firm can trim the edges of that window, adding a delay after the open or a buffer before the close, so your account may become tradeable slightly later and stop slightly earlier than the exchange itself.
What happens at the daily close
In the close window the platform:
Cancels your unfilled orders
Flattens open positions in symbols whose session is closing
Records the day's end-of-day figures and resets your daily baseline
Futures positions are not held across the daily close. This is session handling rather than a rule you can breach, so it is not a violation and nothing is held against you. But if you intend to be in a trade tomorrow, you have to re-enter it tomorrow.
Why your daily numbers reset
The same close sets the starting balance your next day's figures are measured against. Your daily P&L and your daily loss limit both work from that baseline, which is why a daily lockout lifts when the new session opens rather than at midnight.
Crypto is different
Bitcoin perpetual futures trade 24 hours a day, 7 days a week, and are exempt from the futures close. Crypto positions do carry over.
Because there is no natural daily boundary, your firm sets its own crypto day-end time and timezone. That is what drives your daily resets and snapshots on crypto, so your crypto day may roll at a different moment from your futures day.
Weekends belong to crypto only. If your account trades futures alone, there is nothing running until Sunday evening.